JPH11280540A - Cylinder fuel injection engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform accurate air/fuel ratio control by maintaining a tip end temperature of a fuel injection valve lower than a fuel distillation temperature, in a cylinder fuel injection engine arranging a crankshaft in a vertical direction. SOLUTION: In an engine arranging a crankshaft in a vertical direction, a cylinder head 8 connected to a cylinder body 7, fuel injection valve fixed to this cylinder head 8, main cooling water passage 92 formed in a combustion chamber wall outer surface of the cylinder head 8, and a sub-cooling water passage 91 formed in a combustion chamber wall of the cylinder head are provided, in this constitution, a bypass passage 95 is provided in the vicinity of the fuel injection valve and between the main cooling water passage 92 and the sub-cooling water passage 91.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of injecting high-pressure fuel into a cylinder in an engine having a crankshaft arranged vertically.

[0002]

2. Description of the Related Art In a two-stroke engine, unburned gas such as HC is apt to be exhausted because there is a timing at which a scavenging port and an exhaust port are simultaneously communicated. Unburned gas is easily exhausted. Therefore, after the exhaust port is closed, high-pressure fuel is directly injected into the cylinder to atomize the fuel and improve combustion, and at low speed and low load, a large amount of fresh air is supplied to prevent misfiring. A method for reducing the emission of unburned gas is known. When the above-described high-pressure fuel is directly injected into the cylinder, it is necessary to provide a high-pressure fuel pump in the fuel supply system. Conventionally, in a four-cycle engine, a high-pressure fuel pump is driven using rotation of a camshaft of a valve mechanism.

[0003]

In a direct injection type engine, the tip of the fuel injection valve is provided facing the combustion chamber, so that the tip of the fuel injection valve is somewhat cooled by the injected fuel. However, it is always exposed to the combustion flame and becomes hot. However, if the temperature at the tip of the fuel injection valve is higher than the evaporation temperature of the liquid fuel existing at the tip of the fuel injection valve immediately after the fuel injection (90% distillation temperature of gasoline is 150 to 170 ° C.), the fuel Since heavy components tend to remain at the tip, the heavy components adhere as deposits to the tip and the nozzle, and as a result, especially when deposits excessively adhere near the nozzle, the spray shape of the fuel injection And the fuel injection amount fluctuates, so that accurate air-fuel ratio control cannot be performed, leading to a problem that combustion deteriorates.

Particularly, in an engine such as an outboard motor in which a crankshaft is disposed in a vertical direction, cooling water flows up and down the outer wall surface of a cylinder head, so that the cooling water stagnates in a cooling water passage on the outer periphery of a fuel injection valve. This causes a problem that the cooling of the fuel injection valve becomes insufficient.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems and problems. In a cylinder fuel injection type engine in which a crankshaft is disposed in a vertical direction, the temperature of the tip of a fuel injection valve is determined by the temperature of fuel distillation. It is an object of the present invention to provide an in-cylinder fuel injection engine that can maintain accurate air-fuel ratio and maintain accurate air-fuel ratio control.

[0006]

According to one aspect of the present invention, there is provided an engine in which a crankshaft is disposed in a vertical direction, wherein a cylinder head connected to a cylinder body is provided. A fuel injection valve 13 fixed to the cylinder head, a main cooling water passage 92 formed on the outer surface of the combustion chamber wall of the cylinder head 8, and a sub cooling water passage 91 formed in the combustion chamber wall of the cylinder head. A bypass passage 96 is provided between the main cooling water passage 92 and the sub cooling water passage 91 in the vicinity of the fuel injection valve 13. In the engine 2 disposed in the direction, the cylinder head 8 connected to the cylinder body 7, the fuel injection valve 13 fixed to the cylinder head, and the combustion chamber wall outer surface of the cylinder head 8 A main cooling water passage 92 has been made, the sub cooling water passage 9 formed in the combustion chamber wall of the cylinder head
And cooling water passage extending portions 91a and 91b extending outward from the sub cooling water passage 91 in the vicinity of the fuel injection valve 13 of the sub cooling water passage 91. According to a third aspect of the present invention, in the engine 2 in which the crankshaft 10 is disposed in a vertical direction, the cylinder head 8 connected to the cylinder body 7, the fuel injection valve 13 fixed to the cylinder head, A main cooling water passage 92 formed in the outer surface of the combustion chamber wall of the cylinder head 8 and a sub cooling water passage 91 formed in the combustion chamber wall of the cylinder head 8 are provided. Water passage 92
The bypass passage 96 is vertically arranged between the
The invention according to claim 4 is characterized in that, in claims 1 to 3, a heat transfer material 94 is filled between the fuel injection valve mounting hole of the cylinder head and the fuel injection valve. The in-cylinder fuel injection engine according to any one of claims 1 to 3.

According to a fifth aspect of the present invention, in the first to fourth aspects, a cooling chamber 97 is provided between the fuel injection valve mounting hole of the cylinder head and the fuel injection valve, and the cooling chamber is connected to the main cooling water passage. The invention according to claim 6 is characterized in that a temperature detecting means 99 is provided at the tip 13b of the fuel injection valve 13 and the fuel injection amount is determined by the tip temperature. 8. The method according to claim 7, wherein the correction is performed.
The invention described in claim 6 has a plurality of cylinders,
The fuel injection amount is corrected for each cylinder based on the tip end temperature. The invention according to claim 8 is the two-stroke engine according to claims 1 to 7, wherein the fuel injection valve 13 is connected to an exhaust port. It is characterized by being arranged closer to 7k. Note that the numbers added to the above configuration are compared with the drawings for easy understanding of the present invention, and the present invention is not limited thereto.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of an outboard motor showing one example of an in-cylinder fuel injection type engine to which the present invention is applied, wherein FIG. 1A is a plan view of the engine, and FIG.
FIG. 3C is a longitudinal sectional view taken along the line BB, FIG. 3C is a side view of the outboard motor, and FIG. 3D is a configuration diagram of a fuel supply system.

In FIG. 1, reference numeral 1 denotes an outboard motor, an engine 2 having a crankshaft 10 mounted vertically, a guide exhaust portion 3 connected to a lower end surface of the engine 2 and supporting the engine 2, and a guide An upper case 4, a lower case 5, and a propeller 6 connected to the lower end surface of the exhaust unit 3. The engine 2 is an in-cylinder injection V-type six-cylinder two-stroke engine, in which six cylinders 7a to 7f are horizontally arranged and vertically arranged in two rows so as to form a V bank in plan view. A cylinder head 8 is connected and fixed to the cylinder body 7.

A piston 11 is provided in each of the cylinders 7a to 7f.
Are slidably fitted, and each piston 11 is connected to the crankshaft 10. A solenoid opening / closing type fuel injection valve 13 and an ignition plug 14 which are opened and closed by magnetic force are inserted into the cylinder head 8. Cylinders 7a to 7
f is communicated with the crank chamber 12 by a scavenging port (not shown), and an exhaust passage 15 is connected to the cylinders 7a to 7f. In FIG. 1B, the exhaust port 15 of the left bank is joined to the left collective exhaust passage 16, and the exhaust passage 15 of the right bank is joined to the right collective exhaust passage 17. An intake passage 19 branching from an intake manifold is connected to the crank chamber 12 of the engine 2. A reed valve 2 for backflow prevention is connected to a connection portion of the intake passage 19 to the crank chamber 12.
And an oil pump 21 for supplying oil into the engine upstream of the reed valve 20.
A throttle valve 22 for adjusting the intake air amount is provided.

As shown in FIG. 1 (D), the fuel in a fuel tank 23 installed on the hull side is passed through a filter 26 by a manually operated first low-pressure fuel pump 25 to a second fuel tank 23 on the outboard motor side. To the low-pressure fuel pump 27. The second low-pressure fuel pump 27 is a diaphragm pump driven by a pulse pressure of the crank chamber 12 of the engine 2, and supplies fuel to a vapor separator tank 29 serving as a gas-liquid separation device.
Send to A fuel precompression pump 30 driven by an electric motor is provided in the vapor separator tank 29, and pressurizes the fuel and sends it to a high pressure fuel pump 32 via a precompression pipe 31. The discharge side of the high-pressure fuel pump 32 is connected to each cylinder 7
fuel supply rails 3 arranged longitudinally along a to 7f
3 and connected to a vapor separator tank 29 via a high-pressure regulating valve 35, a fuel cooler 36, and a return pipe 37. A preload pressure adjusting valve 3 is provided between the preload pipe 31 and the vapor separator tank 29.
9 are provided.

The high-pressure fuel pump 32 is driven by a pump drive unit 40. This pump drive unit 40
Is connected to the crankshaft 10 via a belt 41. The fuel in the vapor separator tank 29 is pre-pressed by a fuel pre-compression pump 30 to, for example, about 3 to 10 kg / cm ² , and the pressurized fuel is added by a high-pressure fuel pump 32 to about 50 to 100 kg / cm ² or more. As for the high-pressure fuel that has been pressurized and pressurized, surplus fuel exceeding a set pressure by a pressure regulating valve 35 is removed from the vapor separator tank 29.
And supplies only the necessary high-pressure fuel to the fuel supply rail 33.
And the fuel injection valve 13 attached to each of the cylinders 7a to 7f
To supply it.

An ECU (electronic control unit) 42 receives detection signals from various sensors indicating the driving state of the engine 2 and the state of the outboard motor 1 and the boat. For example, the crankshaft 10
Engine speed sensor 4 for detecting the rotation angle (rotation speed) of the engine
3. Intake air temperature sensor 4 for detecting the temperature in the intake passage 19
4. A throttle opening sensor 45 for detecting the opening of the throttle valve 22, an air-fuel ratio sensor 46 for detecting the air-fuel ratio in the uppermost cylinder 7d, a fuel pressure sensor 47 for detecting the pressure in the high-pressure fuel pipe, and an engine. A cooling water temperature sensor 48 for detecting the temperature of the cooling water is provided. The ECU 42
The detection signals of these sensors are subjected to arithmetic processing based on the control map, and the control signals are transmitted to the fuel injection valve 13, the spark plug 14, the oil pump 21, and the preload fuel pump 30.

FIG. 2 is a plan view of the engine 2 of FIG. The same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. A drive pulley 50 is provided on the crankshaft 10, a driven pulley 52 is provided on a rotation shaft 51 of the pump drive unit 40, and a belt 41 is stretched between the drive pulley 50 and the driven pulley 52. I have. As a result, the rotation of the crankshaft 10 is
1 to drive the high-pressure fuel pump 32.

A mounting stay 53 is fixed to the cylinder body 7, and the pump driving unit 40 is connected to the mounting stay 5.
3 and three bolts 54, 55, 5 on the cylinder body 7.
6 attached. Also, the fuel supply rail 3
3 has a horizontal rail 33a and a vertical rail 33b connected to both sides of the horizontal rail 33a, and the fuel injection valve 13 is mounted on the vertical rail 33b. The high-pressure fuel pump 32 has a fuel supply / discharge unit 60 and a fuel outlet pipe 60.
a is connected to the horizontal rail 33 a of the fuel supply rail 33. In the drawing, 1a is a cowling that covers the engine 2, 57 is a starter motor, 58 is a tension pulley,
59 is a silencer.

FIG. 3 is a partial sectional view seen from the Y direction in FIG. FIG. 3 shows a state in which the pump drive unit 40 is mounted by the bolt 54 via the mounting stay 53 as described with reference to FIG. A cam 40 a is fixed to the rotating shaft 51 of the pump drive unit 40, and the cam 40 a is a plunger 32 of the high-pressure fuel pump 32.
It is configured to generate high-pressure fuel by pressing a.

The high-pressure fuel pump 32 is attached to the pump drive unit 40 by four bolts 61. In this bolt connection, the bolt hole on the pump drive unit 40 side is made slightly larger than the diameter of the bolt 61, and when the high-pressure fuel pump 32 and the pump drive unit 40 are mounted, a slight loosening is possible between them.

The engine 2 has a plurality of cylinders 7a to 7f arranged in two rows so as to form a V bank. A fuel supply rail 33 has a vertical rail 33b fixed to the cylinder head 8 in each row and a vertical rail 33b. A horizontal rail 33a is connected to the upper end of the rail 33b. The horizontal rail 33a and the vertical rail 33b are connected by bolts 62. The fuel passage 6 is provided inside the horizontal rail 33a and the vertical rail 33b.
3 is formed, and a connector 65 sealed with an O-ring 64 is provided at a connection portion between the two. The two vertical rails 33b are fixed to the cylinder head 8 by bolts 66, respectively, and the fuel injection valve 13 is fixed to the vertical rail 33b by bolts 67. This bolt 67
Is set to be close to the fuel injection valve 13.

The fuel supply / discharge unit 60 includes a fuel outlet pipe 60.
a, a fuel inlet pipe 60b, and an overflow pipe 60c.
Are connected to the fuel passage 63 of the horizontal rail 33a by a connector 70 sealed with an O-ring 69. The overflow pipe 60c is connected to the vapor separator tank 29. In addition, the high pressure regulating valve 35
Is connected to the pump drive unit 40 by bolts 68 (FIG. 4).
And a connector 72 sealed with an O-ring 71
Is connected to the fuel passage 63 of the horizontal rail 33a.

FIG. 4 is a partial cross-sectional view seen from the X direction in FIG. FIG. 4 shows the mounting structure of the pump drive unit 40 using the mounting stay 53 described above and the fuel supply rail 3.
3 and the details of the mounting structure of the fuel injection valve 13 are shown. The mounting stay 53 is fixed to two bosses 73 formed on the cylinder body 7 by bolts 74.
The pump drive unit 40 is mounted to the mounting stay 53 by bolts 54 and 55, and further fixed to a boss 82 (FIG. 5) of the cylinder body 7 by bolts 56.
The pump drive unit 40 and the high-pressure fuel pump 32 are fixed to the cylinder body 7 at three points. By using the mounting stay 53 in this manner, the pump drive unit 40 and the high-pressure fuel pump 32 can be mounted so as to overhang between the V banks of the cylinder body 7.

The vertical rail 33b of the fuel supply rail 33
Is fixed to a boss 75 formed on the cylinder head 8 by bolts 66, and a horseshoe-shaped spacer 76 is disposed between the flange 13a formed on the fuel injection valve 13 and the vertical rail 33b. Vertical rail 3
The fuel injection valve 13 is fixed to the vertical rail 33b by fixing 3b with a bolt 67. An O-ring 78 is provided on the fuel passage 63 side of the fuel injection valve 13, and on the combustion chamber 79 side of a shaft hole 81 of the cylinder head 8,
An elastic metal seal 80 made of a disc spring is provided. The shaft hole 81 of the cylinder head 8 is made slightly larger than the outer diameter of the fuel injection valve 13, and allows a slight play between the two when the fuel injection valve 13 is mounted.

FIG. 5 is an exploded perspective view of FIG. 2 to FIG. 4. The pump drive unit 40, the high-pressure fuel pump 32, the high-pressure pressure regulating valve 35, the fuel supply rail 33 and the fuel injection valve 13 are used in the present invention. The related high-pressure fuel injection unit 90 is shown. The engine 2 of the high-pressure fuel injection unit 90
A method of attaching the cable to the vehicle will be described with reference to FIGS.

First, the mounting stay 53 is fixed to the cylinder body 7 with bolts 74, and the pump driving unit 40
A high-pressure fuel pump 32 and a high-pressure regulating valve 35 are integrally mounted on the cylinder body 7 and a mounting stay 53, and temporarily fixed to the cylinder body 7 by bolts 54, 55 and 56. On the other hand, the fuel supply rail 33
After connecting the horizontal rail 33a and the vertical rail 33b, and mounting and integrating the fuel injection valve 13 on the vertical rail 33b,
The fuel outlet pipe 60a of the fuel supply / discharge unit 60 and the high pressure regulating valve 35 are connected to the horizontal rail 33a by connectors 70 and 72, respectively, and at the same time, the fuel injection valve 13 is inserted into the shaft hole 81 of the cylinder head 8 and the vertical rail 33b Is temporarily fixed to the cylinder head 8 with the bolt 67.

The play of the connection between the pump drive unit 40 and the high-pressure fuel pump 32 by the bolt 61 and the play of the fuel injection valve 13 and the shaft hole 81 of the cylinder head 8 provide
The bolts 61 and 67 are fully tightened while adjusting the tolerance of each member of the high-pressure fuel injection unit. At this time, the elastic metal sealing member 80 disposed on the outer periphery of the nozzle 13b is pressed and contracted by the final tightening of the bolt 67, and thereby the fuel injection valve 13
And the combustion gas is prevented from leaking from the shaft hole 81.

With the above-described mounting structure, the high-pressure fuel injection unit can be integrated to increase its rigidity, and at the time of assembling the unit to the engine, the integration tolerance can be absorbed to improve the assemblability. Further, the connection between the high-pressure fuel pump and the high-pressure regulating valve and the fuel supply rail can be easily performed, and the strength problem of the conventional flexible pipe or metal pipe can be solved. It is effective for machines.

Next, a description will be given of a cooling structure of the tip portion of the fuel injection valve, which is a feature of the present invention. 6 to 9 show one embodiment of the in-cylinder fuel injection engine of the present invention, FIG. 6 is a cross-sectional view of the cylinder, FIG. 7 is a schematic diagram showing the flow of cooling water, and FIG.
9 is a plan view of the cylinder head body viewed from the inside, FIG.
9A is a plan view as viewed from the back side of FIG. 8, and FIG. 9B is a cross-sectional view as viewed in the direction of the arrow along the line BB of FIG. 9A.

In FIG. 6, the cylinder head 8 comprises a head body 8a and a cover member 8b fixed via a gasket 8c, and a main cooling water passage 92 formed on the outer surface of the combustion chamber 79 wall of the head body 8a. An arc-shaped sub cooling water passage 91 formed in the wall of the combustion chamber 79 of the head main body 8a is formed, and a return passage 93 is formed with respect to the main cooling water passage 92 via a gasket 8c. on the other hand,
A similar arc-shaped cooling water passage 85 is also formed around the cylinder 7 a of the cylinder body 7, and a communication hole (not shown) formed at a predetermined position of the gasket 83 with a sub cooling water passage 91 on the cylinder head 8 side. ) Is communicated through.

As shown in FIG. 7, the cooling water is supplied from the cooling water pump through the cooling water passages 85 of the cylinders 7a to 7c of the cylinder body 7 from the bottom to the top. This time, the cooling water flows through the cooling water passage 91 from top to bottom, and then the cooling water is supplied to the main cooling water passage 92 from bottom to top, and falls down the return passage 93 via the thermostat. 8, the sub cooling water passage 91 of the cylinder body 7 extends from the main cooling water passage 9 below the head body 8a.
2 is provided with a water supply port 92a to
As shown in the figure, the space between the cylinders 7a and 7b and the cylinder 7b
A water supply hole 92b from the sub cooling water passage 91 to the main cooling water passage 92 is provided between the first cooling water passage 91 and the cylinder 7c. Cylinder 7d ~
The same applies to 7f.

In this embodiment, as shown in FIGS. 6 and 8, a sub cooling water passage 91 of the head main body 8a extends outward from the sub cooling water passage 91 in the vicinity of the fuel injection valve 13. The cooling water passage extending portion 91a is provided, and the fuel injection valve 1
3 and its tip 13b are cooled. The shaft hole of the mounting boss 86 of the fuel injection valve 13 formed in the head main body 8 is filled with a heat transfer material 94 having good thermal conductivity made of silicon rubber, silicone resin or the like.
The heat of the three tip portions 13b is released.

As shown in FIGS. 7 and 9, a bypass passage 95 is provided for communicating the sub cooling water passage 91 and the main cooling water passage 92 on the cylinder head 8 side, and cools the vicinity of the side of the fuel injection valve 13. I am trying to do it.

FIGS. 10 to 12 show another embodiment of the in-cylinder fuel injection type engine of the present invention. FIG. 10 is a schematic view showing the flow of cooling water. FIG. 11 (A) shows the cylinder head body viewed from the inside. FIG. 11 (B) is a plan view of FIG.
FIG. 12A is a cross-sectional view taken along the line B in the direction of the arrow, FIG. 12A is a plan view seen from the back side of FIG. 11, and FIG.
FIG. 6A is a cross-sectional view in which the cover member is fixed to the head main body in FIG. The portion Y shown in FIG. 9 of the above-described embodiment has a problem that cooling water stagnates and the temperature at the tip of the fuel injection valve 13 rises because the mounting wall 8d for the ignition plug 14 and the fuel injection valve 13 is present. The present embodiment solves this. In the following embodiments, the same components as those described above will be assigned the same reference numerals and explanations thereof will be omitted.

In the present embodiment, as shown in FIG. 11, the lower part of the cylinder 7a, the upper part and the lower part of the cylinder 7b, A cooling water passage extending portion 9 extending from the sub cooling water passage 91 toward the main cooling water passage 92 above the cylinder 7c.
1b, the upper part of the cylinder 7a, the cylinder 7a and the cylinder 7
b and between the cylinder 7b and the cylinder 7c, a thick portion 91c is provided to block the flow of cooling water from above to below in the sub-cooling water passage 91, so that stagnation is eliminated and smooth. Cooling water is allowed to flow.

Further, as shown in FIGS. 10 and 12,
A bypass passage 96 communicating from the main cooling water passage 92 to the sub cooling water passage 91 is provided at a lower portion and an upper portion of the mounting wall 8d of the ignition plug 14 and the fuel injection valve 13 so that the cooling water flows to the stagnation portion Y. The vicinity of the injection valve 13 is cooled. That is, in FIG. 11, the cooling water flows from the top to the bottom in the sub cooling water passage 91 on the left side of the head main body 8a, flows from the bottom through the main cooling water passage 92 from the water supply port 92a, and a part of the cooling water. Flows through the sub cooling water passage 91 on the right side of the head main body 8a from below, flows from the cooling water passage extending portion 91b at the top of each cylinder to the main cooling water passage 92, and then flows through the cooling water at the bottom of each cylinder. The cooling water flows from the passage extending portion 91b to the sub cooling water passage 91 again, and the cooling water flows to the stagnation portion Y, so that the vicinity of the fuel injection valve 13 is cooled.

FIG. 13 is a sectional view of a cylinder showing another embodiment of the present invention. In the present embodiment, the inside of the mounting boss 86 of the fuel injection valve 13 is a cooling chamber 97, an O-ring 98 is provided between the flange 13 a of the fuel injection valve 13 and the inner surface of the mounting boss 86, and the cooling chamber 97 is connected to the inlet. 97a, exit 97b
The fuel injection valve 13 is cooled by the cooling water from the main cooling water passage 92 so as to communicate with the main cooling water passage 92. In particular, in an outboard motor, since the cooling water flows directly from the lower part of the engine, the fuel injection valve of the lower cylinder is easier to cool. Therefore, the cooling water passage diameter of the fuel injection valve of the upper cylinder (inlet 97a, outlet 97 97b diameter)
It is effective if is made larger than that of the lower cylinder.

14 and 15 show another embodiment of the present invention. FIG. 14 is a sectional view of a cylinder, and FIG. 15 is a view for explaining a control method. In the present embodiment, a temperature detecting means 99 is provided at the tip 13 b of the fuel injection valve 13,
The following control is performed.

As the temperature of the tip 13b of the fuel injection valve 13 increases, heavy components in the fuel tend to remain at the tip, so that the heavy components adhere as deposits to the tip and the injection port, As shown in FIG. 15A, the rate of decrease in the fuel injection amount increases, but when the engine operation elapsed time reaches a predetermined value, the injection amount becomes substantially constant. Therefore, control is performed so as to correct the decrease in the injection amount based on the temperature of the tip portion 13b of the fuel injection valve 13 and the elapsed time of the engine operation.

As shown in FIG. 15B, in the outboard motor, the exhaust system is a collective exhaust and the exhaust is discharged into the water, so that the exhaust system is greatly affected by the back pressure. The variation in the combustion temperature due to the difference in the intake air amount causes the variation in the temperature of the tip 13b of the fuel injection valve 13. Therefore, control is performed so as to correct the decrease in the injection amount among the upper, middle, and lower cylinders in accordance with the temperature of the tip portion 13b of the fuel injection valve 13. When the outboard motor is used most frequently at 4000 rpm or more, the upper cylinder has a longer exhaust pipe length and a good combustion state, so the combustion temperature is the highest, and the lower cylinder is collectively exhausted with the upper cylinder. Even the combustion temperature becomes higher.

FIG. 16 is a control flowchart showing a modification of FIGS. First, the injection amount Q ₀ is read, the operation elapsed time T is read, and the injection amount correction value α for the operation elapsed time T is read from the mapped characteristic curve of FIG. 15, and the corrected injection amount Q is calculated as Q = Q ₀ + α. To be determined. According to this method, the tip 13 of the fuel injection valve 13
The correction injection amount can be determined without providing the temperature detection means 99 in b.

Next, another embodiment of the present invention will be described with reference to FIG. In this embodiment, the fuel injection valve 13 has a tip portion 13.
The nozzle b is positioned so as to be as close to the exhaust port 7k as possible. The fuel injected from the fuel injection valve 13 is distributed (F shown in FIG. 14) toward the exhaust port 7k due to the scavenging flow from the scavenging ports 7h and 7i. The temperature is low,
Accordingly, there is an effect that the temperature of the tip portion 13b of the fuel injection valve 13 is unlikely to become high.

FIG. 17 shows another embodiment of the present invention.
It is a top view of the outboard motor applied to the four-stroke engine.
Also in the present embodiment, the pump drive unit 40 is disposed at the center of the engine 2, and the high-pressure fuel pumps 32 and 34 are disposed on both sides of the pump drive unit 40. In the figure, 7 is a cylinder body, 8 is a cylinder head, 10 is a crankshaft, 13 is a fuel injection valve, 19 is an intake pipe, 29 is a vapor separator tank, 33 is a fuel supply rail, 9
8 is an intake valve and 99 is a camshaft.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made. For example, in the above embodiment, an example in which the invention is applied to an outboard motor is described. However, the invention is also applied to a marine engine in which an engine is installed on the hull side, or a mobile engine such as a lawnmower or a stationary engine. It is possible.

[0042]

As is apparent from the above description, according to the first aspect of the present invention, in a cylinder fuel injection type engine in which the crankshaft is disposed in the vertical direction, the temperature of the tip of the fuel injection valve is controlled by the fuel. It is possible to maintain the temperature lower than the distillation temperature and perform accurate air-fuel ratio control. According to the second aspect of the invention, it is possible to further maintain the temperature at the tip of the fuel injector low. According to the present invention, the stagnation portion of the main cooling water passage can be eliminated, and furthermore, the tip temperature of the fuel injection valve can be maintained low. The tip temperature can be kept low.

[Brief description of the drawings]

FIG. 1 is a schematic view of an outboard motor showing an example of an in-cylinder fuel injection engine to which the present invention is applied, wherein FIG. 1A is a plan view of the engine, and FIG. FIG. 4C is a longitudinal sectional view taken along line BB, FIG. 4C is a side view of the outboard motor, and FIG. 4D is a configuration diagram of a fuel supply system.

FIG. 2 is a plan view of the engine of FIG.

FIG. 3 is a partial cross-sectional view as viewed from a Y direction in FIG. 2;

FIG. 4 is a partial cross-sectional view as viewed from an X direction in FIG. 3;

FIG. 5 is an exploded perspective view of FIGS. 2 to 4;

FIG. 6 is a cross-sectional view of a cylinder showing one embodiment of the in-cylinder fuel injection engine of the present invention.

FIG. 7 is a schematic diagram showing a flow of cooling water in FIG. 6;

FIG. 8 is a plan view of the cylinder head main body of FIG. 6 as viewed from the inside.

9A is a plan view seen from the back side of FIG. 8, and FIG.
FIG. 9B is a cross-sectional view taken along the line BB of FIG.

FIG. 10 is a schematic diagram illustrating a flow of cooling water according to another embodiment of the in-cylinder fuel injection engine of the present invention.

11 (A) is a plan view of the cylinder head main body of FIG. 10 viewed from the inside, and FIG. 11 (B) is FIG. 11 (A).
FIG. 4 is a cross-sectional view taken along line BB of FIG.

12 (A) is a plan view seen from the back side of FIG. 11, and FIG. 12 (B) fixes a cover member to the head main body of FIG. 12 (A), and shows an arrow along line BB. It is sectional drawing seen in the direction.

FIG. 13 is a sectional view of a cylinder showing another embodiment of the present invention.

FIG. 14 is a cross-sectional view of a cylinder showing another embodiment of the present invention.

FIG. 15 is a diagram for explaining the control method of FIG. 14;

FIG. 16 is a control flowchart showing a modification of FIGS. 14 and 15;

FIG. 17 is a plan view of an outboard motor applied to a four-stroke engine according to another embodiment of the present invention.

[Explanation of symbols]

 7 ... Cylinder body 8 ... Cylinder head 10 ... Crankshaft 13 ... Fuel injection valve 91 ... Sub cooling water passage 92 ... Main cooling water passage 94 ... Heat transfer material 97 ... Cooling chamber 99 ... Temperature detecting means

Claims (8)

[Claims] In an engine having a crankshaft disposed in a vertical direction, a cylinder head connected to a cylinder body, a fuel injection valve fixed to the cylinder head, and an outer surface of a combustion chamber wall of the cylinder head are formed. A main cooling water passage, and a sub cooling water passage formed in the combustion chamber wall of the cylinder head, and a bypass passage is provided between the main cooling water passage and the sub cooling water passage near the fuel injection valve. An in-cylinder fuel injection engine. 2. An engine in which a crankshaft is disposed in a longitudinal direction, a cylinder head connected to a cylinder body, a fuel injection valve fixed to the cylinder head, and a fuel injection valve formed on an outer surface of a combustion chamber wall of the cylinder head. And a sub-cooling water passage formed in the combustion chamber wall of the cylinder head. The sub-cooling water passage extends outward from the sub-cooling water passage near the fuel injection valve. An in-cylinder fuel injection engine provided with a cooling water passage extending portion provided. 3. An engine in which a crankshaft is disposed in a vertical direction, a cylinder head connected to a cylinder body, a fuel injection valve fixed to the cylinder head, and an outer surface of a combustion chamber wall of the cylinder head. A main cooling water passage, and a sub cooling water passage formed in the combustion chamber wall of the cylinder head. The fuel injection valve is interposed between the main cooling water passage and the sub cooling water passage. An in-cylinder fuel injection engine characterized by having a passage. 4. The in-cylinder fuel injection according to claim 1, wherein a heat transfer material is filled between the fuel injection valve mounting hole of the cylinder head and the fuel injection valve. Expression engine. 5. A cooling chamber is provided between a fuel injection valve mounting hole of the cylinder head and a fuel injection valve, and the cooling chamber communicates with the main cooling water passage. 5. The in-cylinder fuel injection engine according to any one of 4. 6. The in-cylinder according to claim 1, wherein a temperature detecting means is provided at a tip of the fuel injection valve, and the fuel injection amount is corrected based on the temperature of the tip. Fuel injection engine. 7. The in-cylinder fuel injection engine according to claim 6, comprising a plurality of cylinders, wherein the fuel injection amount is corrected for each cylinder based on the temperature of the tip. 8. The in-cylinder fuel injection engine according to claim 1, wherein the fuel injection valve is arranged near an exhaust port.